You should have blasted him anyway opossums are known to be common rabies carriers.
I got bit by a rabid cat 2 years ago and the shots hurt like hell and there are a lot of them.
Any animal acting strange like that is a risk.
Make sure all your pets are immunized, that's how I got tagged my cat didn't have the shot and she just went nuts while I was petting her.
I figured in the center of town there was little risk, well that was a painful mistake.